Background. Health behavior theories suggest that high perceived risk for cancer will be associated with screening, but few studies have examined how perceived risk relates to the screening decision process. Objective. To examine relationships between perceived risk of cancer and behaviors during decision making for 3 screening tests. Design. Cross-sectional survey conducted between November 2006 and May 2007. Setting. Nationwide random-digit dial telephone survey. Participants. A total of 1729 English-speaking US adults aged 40 y and older who reported making a cancer screening decision (about breast, colon, or prostate tests) in the previous 2 y. Measurements. Participants completed measures of perceived risk, information seeking, and shared decision-making tendencies. Results. As perceived risk for cancer increased, patients were more likely to seek information about screening on their own (e. g., 35% of participants who perceived a high risk of cancer searched the Internet compared with 18% for those who perceived a low risk, P < 0.001) and in interactions with their physicians. As perceived risk increased, patients were also more likely to consult with more than 1 provider. Gender moderated the shared decision-making preference such that men with high perceived risks were more likely than women with high perceived risks to report they would have preferred more involvement in the decision (35% v. 9%, P = 0.001). Limitations. Cross-sectional data limit causal inferences. Conclusions. Higher perceived risk was associated with greater patient participation, as shown by more information seeking and greater desire for decisional involvement (moderated by gender). The results suggest that perceived risk of cancer could influence patient behavior when deciding about screening.